There have been proposed various mechanisms for detecting and managing the remaining amount of ink in an ink cartridge containing an ink used in ink jet printers and the like.
A method of detecting the ink remaining amount may include, for example, a dot count method, an optical method, and the like.
The dot count method is a method of estimating an approximate ink remaining amount by counting an amount of ink consumed for printing, nozzle cleaning, and the like. This method has a function of warning by displaying on a display of a printer main body or by sounding a buzzer, when the ink remaining amount becomes small.
The optical method is a method of detecting presence or absence of ink by reflection of light which is contacted on a visible ink through a prism part obtained by partially machining a bottom of an ink cartridge into a prism shape.
There has also been proposed an ink cartridge having an IC chip or the like provided with an ink remaining amount detection function.
In order to detect the ink remaining amount in an ink cartridge, it is necessary to stabilize a level of ink in the ink cartridge. For example, when a printer or the like having an ink cartridge mounted thereon is installed in a tilted state, the remaining ink amount in the ink cartridge cannot be accurately detected. In particular, in the case of detecting a remaining amount of fuel in a fuel tank of a car or the like, when the car is traveling or stopped on a non-flat road surface, it is difficult to accurately detect the remaining amount of fuel in the fuel tank.
In addition, in the case of detecting a remaining amount of liquid such as an ink or a fuel, when a liquid container and its content is predetermined, it is possible to detect the remaining amount of the liquid by comparing a preset detection reference capacitance value corresponding to the container and the content with a level of the liquid. In this case, it is necessary to prepare a dedicated IC and a memory for storing the detection reference capacitance value and enabling it to be read out when necessary. However, if an IC or the like is prepared for each product, for example, for each ink cartridge, this may result in an increase in cost and time required for designing the product.
In addition, in the case of mounting an ink cartridge for color printing on an ink mounting unit or the like of a printer main body, it is necessary to mount ink cartridges prepared for different colors in respective predetermined positions in the ink mounting unit.